SUBCOOLED CONVECTIVE BOILING OF BINARY-MIXTURES OVER AN ARRAY OF HEATED ELEMENTS

Boiling data and the critical heat flux conditions are reported for bo th channel flow and jet impingement flow using varying concentrations of R-11 in R-113. An array of 10 flush-mounted heated elements on one wall of a vertical passage was cooled by subcooled boiling. Data indic ate that for channel flow boiling, the addition of R-11 to R-113 does not produce a significant change in the critical heat flux condition. For channel flow boiling, the data indicate that addition of a small a mount of a less volatile component slightly increased the critical hea t flux, whereas, the addition of a small amount of a more volatile com ponent decreased it. The critical heat flux data for channel flow were also found to agree well with critical heat flux correlations for pur e fluids if the mole-weighted mean properties of the mixture were used to compute the critical heat flux from the pure fluid correlation. Ho wever, for jet impingement flow with binary mixtures, deviations exist ed between measured data and pure fluid correlation predictions using mole-weighted mean properties of the mixture. The significance of the findings of this study with regard to the use of binary mixtures of di electric fluids for immersion cooling of electronic components is disc ussed in this article.